In 1965, Karl Popper and Thomas Kuhn meet in London
at the International Colloquium in the Philosophy of Science, and while
the two made initial attempts to downplay their differences, it soon
became apparent that they disagreed in the most fundamental of ways. For
Popper, Kuhn's position seemed to undercut the objectivity of science and
to threaten the very rational basis of the scientific enterprise. Kuhn's
stress on paradigms and revolutions seemed to make scientific reasoning more a phenomena of group
psychology and even metaphysical faith than the objective, independently
testable standards that Popper believed science should abide by.
While Popper was willing to concede that what Kuhn described as
"normal science" did go on, to conduct research in this way was
to "fail" at its rational standards.

Kuhn, on the other hand, objected to being labeled
an irrationalist or a fideist. There are good reasons for a scientist to
continue to hold to a theory after an initial failure to obtain the
desired experimental results. He insisted that Popper's normative
standards of falsification really only apply to certain revolutionary moments of science, not the
large majority of its daily practice. Indeed, even in some revolutionary
cases the new paradigm replaced the old one before it was successfully
refuted. While, Kuhn admitted that in one sense he might be judged a
relativist, in another sense he was not. Essentially, Kuhn insisted, that
while he held that there can be no theory-independent access to what is
"really there," he nonetheless holds that science has made
progress in ways that can be seen across paradigms. He insists that the
search for an absolute truth to scientific findings is counter-productive
and really matters very little in the long-run.

Imre Lakatos--Lakatos sought to bridge the
gap between the descriptive model that Kuhn offered and the prescriptive
one that Popper taught. In what he called "the methodology of
scientific research programmes," he stressed that scientific research
is really a series of theory-systems, that is a changing set of
experiments and ideas that contain a "hard core" (i.e. the
central assumptions) which the researchers involved attempt to protect via
a network of auxillary assumptions, what Lakatos calls its "negative
heuristic."

Rather than describe the research "programme"
as true or false, one should see them as either progressing or
degenerating. Commitment to a theory can offer important epistemic
payback, provided that the reworking of the system continues to offer
progress (a "positive heuristic") via new information, continued
testability, more precision, and so on. However, once a programme fails to
do so and only makes ad hoc changes to protect itself, it begins to
degenerate. A degenerating programme sounds its death knells once
its encounters a progressive one with a rival hard core of theory.

Paul Feyerabend--Feyerabend, on the other
hand, argued in works like Against Method that scientists never
actually follow the methodological rules set down as normative for
science, and indeed in many revolutions to do so would have impeded actual
progress. To insist that new theories are consistent with older theories
gives an "aesthetic" privilege to the past. The criteria of
falsification is especially misguided since no theory with any real
explanatory power and interest can account for all the facts. He
recommended a "scientific pluralism," in which practitioners of
various theories are forced to better articulate their models through
robust comparison. Feyerbend also thought claims of incommensurability
could lead to a retarded progress; better to indulge in something like
"scientific anarchism." He even held that science and society
needed something like a legal wall of separation since the arrogance of
science closed itself off too easily to other mythical descriptions of
reality. Feyerabend, perhaps in a catty mood, called Lakatos his fellow
"anarchist" and claimed that Lakatos' model was really his own using
other terminology.

Social Construction--Social constructionists
of science are perhaps the disciples Kuhn never wanted. To say that
something is socially constructed is to argue that everyday life can only
be interpreted as meaningful by members of a social group. This position
can take moderate and radical forms. A moderate approach to social
constructivism stresses that the truth or falsity of a scientific claim is
found within social appeals and practices, not in extra-theoretical
appeals. David Bloor, for
example, advocated what he called the "strong programme" in the
sociology of scientific knowledge, namely that all knowledge must have a
social element because all perception is theory-laden. In this way, Bloor
is a Kantian--science cannot finally access the Ding an Sich, the
"thing in itself." Thus, there are no "supra-social
standards" by which one may judge the content of science. Bloor sets
out the strong programme this way:

1. It
would be casual, that is, concerned with the conditions which bring about
belief or states of knowledge. Naturally there will be other types of
causes apart from social ones which will cooperate in bringing about
belief.

2. It
would be impartial with respect to truth and falsity, rationality or
irrationality, success or failure. Both sides of these dichotomies will
require explanation.

3. It
would be symmetrical in its style of explanation. The same types of cause
would explain, say, true and false beliefs.

4. It
would be reflexive. In principle its patterns of explanation would have to
applicable to sociology itself. Like the requirement of symmetry this is a
response to the need to seek for general explanations. It is an obvious
requirement of principle because otherwise sociology would be a standing
refutation of its own theories.

Science
sees what its members are trained to see, and sociologists of science
would seek not to make judgments as to the truth or falsity of its
findings because truth and falsity can never be ascertained outside social
conventions of understanding, including that of the sociologist of
science. A more radical approach to social constructivism, such as
that taken by Bruno Latour, Michel Callon, or Steve Woolgar, insists thatscientific networks are a self-contained reality, that
science is about its practice not a real world outside itself--in a sense,
the "real world" is created by social practice and theory.
Another expression of radical constructivism can be seen in feminist
science criticism. Social constructionists pay close attention to the
metaphors that inform scientific theory and dialogue, metaphors which they
charge reveal much about the social dimension of the practice. Feminists
critics, such as Sandra Harding, charge that the rhetoric of much male
science (including non-feminist female science) is full of imagery of
power, rape, and abuse, and this imagery reveals the epistemic limits of
its findings.

According to Larry Laudan, as of
1981 the state of the search for a philosophy of science and its history
can be said to be that:

(1) Theory transitions
are generally non-cumulative, i.e., neither the logical nor empirical
content (nor even the confirmed consequences) of earlier theories is
wholly preserved when those theories are supplanted by newer ones.

(2) Theories are
generally not rejected simply because they have anomalies nor are they
generally accepted simply because they are empirically confirmed.

(3) Changes in, and
debates about, scientific theories often turn on conceptual issues
rather than on questions of empirical support.

(4) The specific and
'local' principles of scientific rationality which scientists utilize in
evaluating theories are not permanently fixed, but have altered
significantly through the course of science.

(5) There is a broad
spectrum of cognitive stances which scientists take towards theories,
including accepting, rejecting, pursuing, entertaining, etc.Any theory of rationality which discusses only the first two will
be incapable of addressing itself to the vast majority of situations
confronting scientists.

(7) Given the notorious
difficulties with notions of 'approximate truth'- at both the semantic
and epistemic levels- it is implausible that characterizations of
scientific progress which view evolution towards greater truth-likeness
as the central aim of science will allow one to represent science as a
rational activity.

(8) The
co-existence of rival theories is the rule rather than the exception, so
that theory evaluation is primarily a comparative affair.

Realism and Antirealism

At the heart of the Pandora's box that Kuhn, perhaps
unwittingly and unintentionally, opened are the related questions as to
whether the various sciences examine a common reality, whether an actual
order is uncoverable in the universe other than the one that a theory
imposes on it, and whether theories can be said to be "real" in
any fundamentally actual manner. Janet A.
Kourany suggests that this debate can be formulated this way:

1.Do the theories of science give a literally true account of the
way the world is? Or are they mere calculating devise, useful fictions,
convenient methods of representations, only empirically adequate but not
true, or only true in some non-literal sense?

2.Under what conditions is it reasonable to accept a theory on a
realistic interpretation (as literally true) rather than on an
instrumentalist interpretation (as not literally true, but convenient
for summarizing, systematizing, deducing, and so on a given body of
information)?

3.Under what conditions is it reasonable to accept the entities
postulated by a theory (and this includes processes, states, fields, and
the like) as real existents rather than as mere hypothetical entities?

The two broad camps of
realism and anti-realism can be divided by those who affirm that science
in some way describes the actual world and those who say that it is at
best always a description of our interactions with the world.

Realism Antirealism

Grover Maxwell--The line between
observation and theory is always an arbitrary one; and all objects could
be potentially observable. What counts as observable is itself a
theoretical question, so the distinction has no real value.

Bas van Fraassen--"Empirical adequacy" is
the best a scientist can claim about any theory; the observation-theory
distinction can be made though admittedly "observation" is
always a vague predicate, which can only be used in a functional manner.

The Ultimate Argument fails because the success of
science is like Darwinian evolution; the strongest theories survive due to
their empirical adequacy in handling the physical world.

Hilary Putnam--The Ultimate Argument--If
the mathematical and physical experiences of science are not about the
actual world, then the success of science is a "miracle," which
is simply ludicrous.

Philip Kitcher--A consistency exists
between observational findings and theories because of the comparative
nature of science. One is always checking one's theory against the
observations.

Larry Laudan--The history of
science shows numerous examples of theories that were successful yet not
actually referential to objects we now believe to exist; likewise, a
number of examples can be offered of unsuccessful theories that did refer
to genuine objects in the world.

Alan Musgrave--The realist is taking no
more risk by betting on the actual real findings than the antirealist is
by relying on empirical adequacy. Realism offers the most epistemic
benefit. Antirealists haven't explained why some theories survive
and others do not.

Ian Hacking--Experimental
realism--Scientists form beliefs about objects by interacting with them.
Theoretical terminology refers to actual unobservable referents, even if
the terminology shifts over time. Beliefs about what we observe and cannot
yet observe are similar, so we need not commit to the referential truth of
theories to commit to the observational truths of experimentation.

Arthur Fine--Natural Ontological
Attitude (NOA)--Accepting the results of science as "true" in an
ordinary day-to-day manner does not commit one to the long-term survival
of its truth or to the ability of science to uncover the final
"Truth" of existence.